[ntp:questions] .1 Microsecond Synchronization

Richard B. Gilbert rgilbert88 at comcast.net
Thu Jun 4 19:03:18 UTC 2009

Terje Mathisen wrote:
> John Hasler wrote:
>> ScottyG writes:
>>> Has anyone had any experience doing this? Can anyone suggest how to
>>> achieve this accuracy?
>> Talk to the very long baseline radio astronomers.
>>> We do have some budget but this but if I need to spend a whole lot on
>>> this I need to get in front of my management with the reasons.
>> You will need to.  Has someone already gotten in front of them with the
>> reasons for this accuracy?
>> Of course, recording timestamps with 100 nanosecond _precision_ is easy.
> That is probably the real requirement:
> Windows' os clock runs with 100 ns ticks, but the actual resolution and 
> accuracy is normally 10-17 ms.
> That said, yes you can get down to sub-us timestamps, but it requires 
> dedicated hardware to do so:
> First you must have a timing-optimized gps receiver, then you need some 
> hardware which can be slaved to the pps signal from that gps, and which 
> can also be used as the time base of all your logs.
> I.e.a PCI card or similar which your apllications can query directly to 
> get the current timestamp.

ISTR that both Symmetricomm and Meinberg Funkurhren offer such cards at 
prices somewhere betwen $1250 and $2500; IOW they are not cheap!!  I 
believe that both support an optional GPS receiver.  For more money, of 

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